Diagnostic instrument



Feb. 4, 1947d D, v suMMERviLLE ET AL 2,415,310

DIAGNOSTIC INSTRUMENT Filed Feb. 8, 1945 lll/10,..

2050/ .T a@ 54 4a 36 2? 28 12 '9 ze 4 76 FIG. 5

I I E eo el r 'l so \-74 '2 3e 26 29 l l 35 JNVENTOR. r/ -l 77 DONALD v. SUMMERVILLE 57 BY HOWARD w. NAULTY Patented Feb. 4, 1947 UNlTED STATES PATENT OFFICE DIAGNOSTIC INSTRUMENT tion of New York Application February S, 1945, Serial No. 576,840

(Cl. 12S-2) 4 Claims. 1

This invention relates to an instrument of novel purpose and design. More particularly, it relates to an instrument for measuring the frequency and magnitude of deflection of the tympanum of the human ear under varying atmospheric conditions. This instrument has been named by us a tympanometer. Certain features of the instrument may also be used for other purposes.

In modern aviation, commercial and military airplanes very often ascend to considerable heights in the earths atmosphere. In making such ascents, it is important that the human body be able to withstand without detriment the temperature and pressure changes to which it is subjected. One or" the ways in which pressure changes aiect the human body has been found t be in the form of deflections of the tympanum of the human ear, or the ear drum. These deections often occur at high frequencies. The measurement of the amplitude and frequency of these deections may accordingly be an important factor in determining the ability 0f an individual to withstand high altitude conditions without detriment.

It is therefore an object of this invention to provide an instrument for measuring the amplitude and frequency of deflections of the tympanum of the human ear. Another object is to provide such an instrument which is particularly useful for measuring such deflections at high altitudes. Other objects will appear hereinafter.

These objects are accomplished by the herein described and claimed instrument, which may be more readily understood by reference to the accompanying drawing, in which: Figure `1 is an enlarged longitudinal cross section of the instrument showing its relation to the human ear; Figures 2 and 3 are details of portions of Figure 1 on a still larger scale; Figure 4 is a view taken along the line 4 4 of Figure 1; and Figure 5 is a schematic wiring diagram of the instrument.

Referring now to Figure 1, the instrument itself is encased in a three-piece stainless steel cylindrical housing or frame including an inner section II, an intermediate section I2 and an outer lsection I3. The sections II and I2 are threadably engaged, as shown, with a gasket I4 and a washer l5 interposed between them. The gasket and washer are held in place by means of a series of circumi'erentially spaced dowel pins 4S passing through circular holes in the gasket and washer and aligned in suitable bores in section l2 and an annular groove Il in section II. Sections I2 and I3 are arranged with a sliding t therebetween, and are held together by circumferentially spaced set screws I8 threaded through section i2 and engaging an annular groove I9 in section I3.

The inner section I I is provided with a hollow stem 20 integral therewith and extending axially from its inner end. Fitted over this stem is a rubber' nipple 2I capable of being inserted in the external opening or os of a human ear Ii. Adjacent the inner end of section II there is also provided a peripheral opening from which there extends in a radial direction a hollow funnellike extension 22, interiorly threaded as shown. A removable threaded plug 23 fits into this extension, for the reasons as hereinafter described. The side wall of the extension is provided with a bleeder opening 24, also for reasons as hereineter described.

The intermediate section I2 is provided with a bore in which is slidably ntted a sleeve liner 2E, preferably made out of insulating plastic, such as a polystyrene resin. Both the section I2 and the liner 25 are provided with aligned longitudinal slots 26 and 2l, respectively, in which a tightene ing screw 28 is adapted to ride. A plurality of these slots and tightening screws may be spaced circumferentially about section i2. A collar 29 nts over the shank of each tightening screw to provide a, finger hold by which the screw may be moved. The threaded inner end of each screw 23 engages a correspondingly threaded radial bore in a cylindrical block 30 which is adapted to slide within the liner 25. Thus, in the loosened condition of screws 28, block 30vmay be moved axially by grasping the collars 29. When screws 28 are tightened, however, collars 29 are clamped between the heads of the screws and the peripheral surface of section I2.

The cylindrical block 30 is provided with an axial bore in which a, rod 3| is adapted to slide. This rod rides on jewelled bearings or bushings 32 situated at the opposite ends of block 3d. Referring to Figure 2, the inner end of this rod is threaded for the reception of a pair of hexagonal nuts 33 and 34. Aixed to the inner end of blocl; 3@ is a plate 35 held in place by pins or screws 35. The plate 35 has a central cut-out portion el adapted to nt over the nut 33. Thus it will be seen that nut 34 can be tightened or loosened, while holding nut 33 against rotation, by sliding block 3S until plate 35 fits over nut 33.

Between the nuts 33 and 34 is clamped a diaphragm assembly indicated generally at S. This assembly :consists of a pair of stainless steel washers 39 between which is gripped a flexible rubber diaphragm 4U. The peripheral edges of the diaphragm 40 are gripped between a pair of stainless steel rings il and d2. Ring Ail ts into an annular recess formed between liner 25 and a set-back portion of housing section i2. A ring gasket i3 and a washer dfi, the latter provided with a tab d5 fitting in a corresponding sloi-l in the housing section i2 to prevent rotation thereof, fit against the ring d2. The assemblage of elements of 4t, iii, 62, 1.3 and liLl is held rmly in place against a shoulder on housing section l2 by means of a threaded ring 66 having radial slots il for the insertion of a screw driver or similar tool. The abutting end of the sleeve also assists in holding the diaphragm 46 in place, while a short iianged sleeve G8 of plastic material aligned with sleeve 25 bears against the opposite surface of the diaphragm. The sleeve i3 is properly aligned by means of a plurality of circumferentially spaced aligning pins d mounted on ring dii. It is held in position by means of a compression spring 5d, which in turn is aligned by means of circumferentially spaced aligning pins 5 i It will be seen that the space to the left of diaphragm iii forms a chamber 52 communicating with the exterior only through the funnel extension 22 and the nipple 2i. In use, this space is iilled with water or other liquid, which also fills the interior cavity of the ear between the tympanum and the nipple 2 i. The plug 23 is then screwed into the funnel 22, squeezing out excess liquid through the bleeder opening 2li. The final turn of the screw plug 23 seals 01T the bleeder opening by seating of the plug against an internal shoulder on the extension 22. This must be done rather carefully, to avoid putting x either the tympanum or the diaphragm 45 under tension. The diaphragm di) and its associated clamping rings, washers, gaskets, etc., and also the gasket Hl between sections li and i2 are constructed to avoid leakage from the chamber 52. The chamber or space to the righi; of the diaphragm 46 is in communication with the atmosphere through slots 26 and 2l when the block 3@ is in its normal or operating position, as shown in the drawings, so that this side of the diaphragm is always subjected to atmospheric pressure. A set of through-bores il allows equalization of pressure on opposite sides of the block 3l).

Referring now to Figures 1 and 3, the outer end of sleeve 25 is threadably connected, as indicated, to a special fitting 53, preferably also made out of plastic insulating material. The outer end of tting 5S, in turn, is threaded to a plastic collar 511i. The latter is kept from turning by means of an aligning pin 55, and is held on the end of a threaded stainlesssteel adjusting screw 56 by means of a retaining screw 57. The adjusting screw is threadably engaged with the housing section i3, and can be locked against turning by means of set screw 58. Thus it will be seen that the ensemblage consisting of the plastic elements 48, 25, 53 and 5d can be adjusted axially or longitudinally by turning adjusting screw 5S, so as to secure proper positioning of the diaphragm 4G. Turning the screw clockwise, as viewed from the right, will move the ensemblage to the left against the resistance of spring 5i?, while turning in the opposite direction will eventually cause sleeve to draw away from diaphragm lid,

On the outer end of rod 3i (see Figure 3) there is mounted a cup-shaped tting 5S of insulating plastic material. On the cylindrical surface of gie-layered or multi-layered, and preferably lies in a wide shallow groove, provided for this purpose, on fitting 59. A second coil of wire 6I, preferably multi-layered, is wound on fitting 53 as shown. The two coils G and 6i are electrically connected to the exterior, as hereinafter described. A soft iron core 62 held in the fitting 53 serves as the medium for inducing a :current in coil Si] by means of a current in coil El.

A portion of the cylindrical surface of housing section i2 is cut out, and the cut out portion filled by means of a curved rectangular plate 63 of insulating plastic material held in place by retaining screws Ed. Three metallic binding posts or terminals 65, 65 and B1 are held in this plate 63. A conducting wire 68 connects post B5 with one end of coil $0, and a second conducting wire 69 connects the post 68 to the opposite end of coil 60. The two wires 68 and 69 pass through an elongated slit i6 in element 25, provided for this purpose. A third conducting wire lil connects one end of coil 6| with post 68, and a fourth conducting wire 7| connects the opposite end of coil Si with post Si. Post 66 thus serves as a common ground for both coils Si! and El.

In operation, a high frequency alternating current at a controlled voltage is passed through -there has been provided a simple compact inthis tting a coil of wire 60 is wound, the ends 'other purposes.

a coil 6|, whereby an induced current is set up in coil Sii through the medium of the soft iron core 62. As shown in the drawings, the coil 60 only partially overla'ps iron core 62. As the rod 3i moves back and forth due to movement of the diaphragm (50, the amount of overlap of the coil 6B on core 62 varies, and consequently the induced current and the voltage in coil B varies. From the previous description, it will be seen that any deiiection of the tympanum, due to atmospheric pressure changes or for other reasons, will tend to cause a corresponding change in volume in the chamber 52 and the space between the chamber and tympanum. Since this chamber and space is completely-nlled with a liquid which is relatively incompressible and inexpensible, a wall of the chamber must deflect simultaneously with the tympanum so as to maintain a constant volume. The only place that this can occur with relative ease is at the diaphragm d. Movement of diaphragm il in turn causes a corresponding movement of rod 3l and coil 60. Consequently, it is seen that any deflection of the tympanum causes a change in the induced current passing through coil G.

In Figure 5 there is shown a schematic wiring diagram for use with the instrument shown in Figures 1 to 4 inclusive. An oscillator l2 of conventional type supplies current to the Xed coil 6l at a fixed frequency, such as 24 kilocycles. The voltage of this current is measured and regulated by means of an'adjusting vacuum tube voltmeter 73. The induced current in coil El) is fed into an amplifier it, and the amplied current then fed into a suitable recording instrument l5, such as an oscillograph. For the sake of clearness, the wiring for the two coils is shown entirely separate in Figure 5. In practice, however, as shown in the remaining figures, one terminal on each coil is grounded.

The instrument described above may be attached to the head of the wearer by any suitable harness or head gear, not shown.

From the above description, it will be seen that strument for measuring and recording deflections of the tympanum of the human ear. Certain features of the instrument may also be used for Other variations from the form of the invention described herein are also possible. Thus, the actuating rod 3l may be connected to a variable capacitor instead of a variable inductor. Instead of being Wired, any suitable part of the electrical circuits may be connected to the instrument by radio, as well known in the art. It is understood that the invention is not to be limited except as deiined in the appended claims.

We claim:

l. An instrument for measuring deflections of the tympanum, comprising a nipple for insertion in the natural os of an animate ear` a passageway extending through said nipple, a chamber communicating with said passageway, a readily deiiectable wall bounding said vchamber' on one side thereof and deectable upon movement of liquid through said passageway due to deilection of the tympanum, said chamber when closed be ing substantially liquid tight except on the side communicating with said passageway and being entirely bounded by relatively rigid walls except for said deilectable wall, and means for measuring the delico-tion of said dellectable wall.

2. An instrument for measuring deflections of the tympanum, comprising a, housing, a nipple for insertion in the natural os of an animate ear, a passageway extending through said nipple, a chamber communicating with said passageway, an opening for the introduction of liquid into said chamber, a closure for said opening, a readily deectable wall bounding said chamber on one side thereof and deectable upon movement of liquid through said passageway due to deflection of the tympanum, said chamber when closed being substantially liquid tight eX- cept on the side communicating with said passageway and being entirely bounded by relatively rigid walls except for said deflectable wall, and means for measuring the deflection of said dellectable wall.

3. An instrument for measuring deflections of the tympanum, comprising a housing, a nipple for insertion in the natural os of an animate ear, a passageway extending through said nipple, a chamber communicating with said passageway, an opening for the introduction of liquid into said chamber, a closure for said opening, a readily deflectable wall bounding said chamber on one side thereof and deectable upon movement of liquid through said passageway due to deilection of the tympanum, said chamber when closed being substantially liquid tight except on the side communicating with said passageway and being entirely bounded by relatively rigid walls except for said delectable wall, a movableinductance coil connected to said deectable wall and responsive to deections thereof, a Xed inductance coil, and a core common to both said coils, one of said coils being adapted to carry an alternating current of substantially xed voltage whereby a current is induced in the remaining said coil thro-ugh the medium of said core, and said core being so positioned that the magnitude of said induced current depends upon the position of said movable coil.

4. An instrument for measuring deiectiong o1" the tympanum, comprising a housing, a nipple for insertion in the natural os of an animate ear, a passageway extending through said nipple, a chamber communicating with said passageway, an opening for the introduction of liquid into said chamber, a closure for said opening, a readily deilectable wall bounding said chamber on one side thereof and deflectable upon movement of liquid through said passageway due to deflection of the tympanum, said chamber when closed being substantially liquid tight except on the side communicating with said passageway and being entirely bounded by relatively rigid walls except for said deflectable wall, a movable inductance coil connected to said deflectable wall and responsive to deflections thereof, a lixed inductance coil mounted on said housing, and a nXed core common to both said coils, said xed coil being adapted to carry an alternating current of substantially fixed voltage whereby a current is induced in said movable coil through the medium of said core, and said core being so positioned that the magnitude of said induced current depends upon the position of said movable coil with respect to said core.

DONALD V. SUMMERVILLE. HOWARD W. NAULTY.

REFERENCES CITED UNITED STATES PATENTS Name Date Marcellus Dec. 6, 1938 Number 

